I've used the gym at the GF (free, was a guest), BCV (free, was a cash guest) and VWL (free, was a cash guest). Am planning to use the one at SSR for free, as I will be a cash guest in Dec.
VWL was pretty nice. BCV was nice, although the TVs were sort of high and I got a crick in my neck from watching while running. GF was, honestly, a disappointment....expected better.